I took Ewen's advice - which I usually do - and did a brisk hilly walk this morning. I mightn't be a fast runner but for sure I'm a slow walker! It was to be for 30 minutes.
Anyhow, I did what I was told - which I don't usually do - and set off at a cracking snail's pace, but couldn't get my heart rate past 60% of maximum, so I kept on going, past 30 minutes, until I came to a mighty hill that wound the heart rate up to76%.
All up then, I walked as briskly as a snail can for 57 minutes, covering a distance of 6km for today.
AHR 60%; MHR 76%
Nice day again, too!